Biomaterial Database

Genetic causes of mental handicap and opportunities for prevention. 1988

J M Connor, and M A Ferguson-Smith

Prior to 1970 nearly one half of severe mental handicap (IQ less than 50) was unexplained and genetic causes were recognized in one third of all patients. In recent years the genetic contribution has risen to 50%, with the decline in importance of environmental causes and the growing recognition of X-linked forms of mental retardation and chromosomal microdeletion syndromes. Recognition of genetic conditions is vital for accurate assessment of recurrence risks and in order, in some instances, to provide specific prenatal diagnosis. With full utilization of existing prenatal screening procedures and a more detailed family history, severe mental handicap due to genetic conditions should be reduced by 30-40%.

UI	MeSH Term	Description	Entries
D007231	Infant, Newborn	An infant during the first 28 days after birth.	Neonate,Newborns,Infants, Newborn,Neonates,Newborn,Newborn Infant,Newborn Infants
D008607	Intellectual Disability	Subnormal intellectual functioning which originates during the developmental period. This has multiple potential etiologies, including genetic defects and perinatal insults. Intelligence quotient (IQ) scores are commonly used to determine whether an individual has an intellectual disability. IQ scores between 70 and 79 are in the borderline range. Scores below 67 are in the disabled range. (from Joynt, Clinical Neurology, 1992, Ch55, p28)	Disability, Intellectual,Idiocy,Mental Retardation,Retardation, Mental,Deficiency, Mental,Intellectual Development Disorder,Mental Deficiency,Mental Retardation, Psychosocial,Deficiencies, Mental,Development Disorder, Intellectual,Development Disorders, Intellectual,Disabilities, Intellectual,Disorder, Intellectual Development,Disorders, Intellectual Development,Intellectual Development Disorders,Intellectual Disabilities,Mental Deficiencies,Mental Retardations, Psychosocial,Psychosocial Mental Retardation,Psychosocial Mental Retardations,Retardation, Psychosocial Mental,Retardations, Psychosocial Mental
D010375	Pedigree	The record of descent or ancestry, particularly of a particular condition or trait, indicating individual family members, their relationships, and their status with respect to the trait or condition.	Family Tree,Genealogical Tree,Genealogic Tree,Genetic Identity,Identity, Genetic,Family Trees,Genealogic Trees,Genealogical Trees,Genetic Identities,Identities, Genetic,Tree, Family,Tree, Genealogic,Tree, Genealogical,Trees, Family,Trees, Genealogic,Trees, Genealogical
D001921	Brain	The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.	Encephalon
D002869	Chromosome Aberrations	Abnormal number or structure of chromosomes. Chromosome aberrations may result in CHROMOSOME DISORDERS.	Autosome Abnormalities,Cytogenetic Aberrations,Abnormalities, Autosome,Abnormalities, Chromosomal,Abnormalities, Chromosome,Chromosomal Aberrations,Chromosome Abnormalities,Cytogenetic Abnormalities,Aberration, Chromosomal,Aberration, Chromosome,Aberration, Cytogenetic,Aberrations, Chromosomal,Aberrations, Chromosome,Aberrations, Cytogenetic,Abnormalities, Cytogenetic,Abnormality, Autosome,Abnormality, Chromosomal,Abnormality, Chromosome,Abnormality, Cytogenetic,Autosome Abnormality,Chromosomal Aberration,Chromosomal Abnormalities,Chromosomal Abnormality,Chromosome Aberration,Chromosome Abnormality,Cytogenetic Aberration,Cytogenetic Abnormality
D004314	Down Syndrome	A chromosome disorder associated either with an extra CHROMOSOME 21 or an effective TRISOMY for chromosome 21. Clinical manifestations include HYPOTONIA, short stature, BRACHYCEPHALY, upslanting palpebral fissures, epicanthus, Brushfield spots on the iris, protruding tongue, small ears, short, broad hands, fifth finger clinodactyly, single transverse palmar crease, and moderate to severe INTELLECTUAL DISABILITY. Cardiac and gastrointestinal malformations, a marked increase in the incidence of LEUKEMIA, and the early onset of ALZHEIMER DISEASE are also associated with this condition. Pathologic features include the development of NEUROFIBRILLARY TANGLES in neurons and the deposition of AMYLOID BETA-PROTEIN, similar to the pathology of ALZHEIMER DISEASE. (Menkes, Textbook of Child Neurology, 5th ed, p213)	Mongolism,Trisomy 21,47,XX,+21,47,XY,+21,Down Syndrome, Partial Trisomy 21,Down's Syndrome,Partial Trisomy 21 Down Syndrome,Trisomy 21, Meiotic Nondisjunction,Trisomy 21, Mitotic Nondisjunction,Trisomy G,Downs Syndrome,Syndrome, Down,Syndrome, Down's
D005600	Fragile X Syndrome	A condition characterized genotypically by mutation of the distal end of the long arm of the X chromosome (at gene loci FRAXA or FRAXE) and phenotypically by cognitive impairment, hyperactivity, SEIZURES, language delay, and enlargement of the ears, head, and testes. INTELLECTUAL DISABILITY occurs in nearly all males and roughly 50% of females with the full mutation of FRAXA. (From Menkes, Textbook of Child Neurology, 5th ed, p226)	FRAXA Syndrome,FRAXE Syndrome,Martin-Bell Syndrome,Fra(X) Syndrome,Fragile X Mental Retardation Syndrome,Fragile X-F Mental Retardation Syndrome,Mar (X) Syndrome,Marker X Syndrome,Mental Retardation, X-Linked, Associated With Fragile Site Fraxe,Mental Retardation, X-Linked, Associated With Marxq28,X-Linked Mental Retardation and Macroorchidism,FRAXA Syndromes,FRAXE Syndromes,Fragile X Syndromes,Marker X Syndromes,Martin Bell Syndrome,Syndrome, FRAXA,Syndrome, FRAXE,Syndrome, Fragile X,Syndrome, Marker X,Syndrome, Martin-Bell,Syndromes, FRAXA,Syndromes, FRAXE,Syndromes, Fragile X,Syndromes, Marker X,X Linked Mental Retardation and Macroorchidism
D005820	Genetic Testing	Detection of a MUTATION; GENOTYPE; KARYOTYPE; or specific ALLELES associated with genetic traits, heritable diseases, or predisposition to a disease, or that may lead to the disease in descendants. It includes prenatal genetic testing.	Genetic Predisposition Testing,Genetic Screening,Predictive Genetic Testing,Predictive Testing, Genetic,Testing, Genetic Predisposition,Genetic Predictive Testing,Genetic Screenings,Genetic Testing, Predictive,Predisposition Testing, Genetic,Screening, Genetic,Screenings, Genetic,Testing, Genetic,Testing, Genetic Predictive,Testing, Predictive Genetic
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013577	Syndrome	A characteristic symptom complex.	Symptom Cluster,Cluster, Symptom,Clusters, Symptom,Symptom Clusters,Syndromes